backlash adjustment on CG5 GOTO

yanyewkay · Post by **yanyewkay** » Tue May 29, 2007 12:00 am

I just learnt what backlash was (from a non-astro friend) and saw my CG5-GOTO had the option to set it. The manual recommended some values but I don't see any difference. I had tried from the recommended 20-50 but it didnt' make any difference. I then incresed in steps of 10 untill i hit the maximum. But still don't see any diff.

Anyone knows how to adjust for backlash on this mount?

Post by **weixing** » Tue May 29, 2007 12:20 am

Hi,

But still don't see any diff.

To check whether does the backlash adjustment had any different, try the following and test one axis at a time:
1) First set the traking mode to off and use the slowest speed.
2) Aim the scope at a terrestrial object far away using a high power eyepiece.
3) Press one direction key until the scope start to move.
4) Look through the scope and press the opposite direction button. Measure the time taken for the scope to move.
5) Key in a new Anti-backlash value for that axis and do the test again. Adjust the settings until it cause immediate movement without a sudden jump when pressing or releasing the direction button.

Have a nice day.

yanyewkay · Post by **yanyewkay** » Tue May 29, 2007 12:41 am

ohhhhh.... using high power eyepiece! I was using a 25mm all along... will try it out again tomorrow~ THANKS!!

yanyewkay · Post by **yanyewkay** » Wed May 30, 2007 5:28 pm

using a 10mm eyepiece, have been trying but the backlash is still the same.. i tried values from 0 to 99 in increments of 3 for +ve and -ve for each axis.. the delay is still about 6seconds before moving in the opposite direction

hommel · Post by **hommel** » Wed May 30, 2007 5:52 pm

The backlash adjustment is NOT meant to totally remove backlash in slew speeds lower than 5. Its usage is to eliminate skips/jump, other than that, there's nothing much you can do. as long as the movement is smooth, just leave it as it is.

yanyewkay · Post by **yanyewkay** » Fri Jun 01, 2007 12:25 pm

i was using slew speed of 6 while adjust the backlash.. i think I might want to open up the mount and adjust the gears a bit since it's quite well documented all over

Meng Lee · Post by **Meng Lee** » Fri Jun 01, 2007 12:42 pm

Er, better get someone who has done it before to do it for you. The essential adjustment is 2 pull, 1 push allen screws on each axis. I mean the meshing of the worm gear to the axis gears. The adjustmensts are quite subtle ah!

This reduces the mechanical backlash, then there will still be backlash which you can use the contoller to compensate.

yanyewkay · Post by **yanyewkay** » Fri Jun 01, 2007 12:43 pm

thanks! this is great info..